Commonly used extraction bags include tea bags for black teas, green teas, herbal teas, and other teas and extraction bags containing dried material such as dried small sardine and dried bonito for preparing stock. Such an extraction bag includes a tetrahedral or rectangular bag body formed from a water-permeable filter extraction bag sheet such as a nonwoven fabric sheet, and an extractable material, such as tea leaves, packed in the bag body. If necessary, a hanging string with a tag is attached to the outer surface of the bag body.
Such extraction bags, specifically tetrahedral extraction bags with strings and tags, for example, can be manufactured as follows. An extraction bag sheet prepared by disposing tags and a string used as a hanging string on a strip-like water-permeable filter sheet is shaped into a tubular form by bonding the opposite end portions of the extraction bag sheet to each other. Then the formation of first horizontal bonding by flattening, welding, and cutting the tubular body in a first width direction and the formation of second horizontal bonding by welding and cutting the cut tubular body in a second width direction intersecting the first width direction are performed alternately. An extractable material, such as tea leaves, is packed between the formation of the first bonding and the formation of the second bonding (Patent Documents 1 and 2).
In one exemplary method of packing such bags with an extractable material, an auger screw attached inside a packing pipe for supplying the extractable material from a hopper to a bag body is rotated to supply a predetermined amount of the extractable material to the bag body (Patent Document 3). In another exemplary method, an extractable material stored in a hopper is measured with measures formed in a rotary table and is supplied to a bag body through a chute pipe (Patent Document 4).
[Patent Document 1] Published Japanese Translation of PCT International Application No. 2001-519729
[Patent Document 2] Published Japanese Translation of PCT International Application No. 2006-510550
[Patent Document 3] Japanese Patent Application Laid-Open No. 2003-237701
[Patent Document 4] Japanese Patent Application Laid-Open No. 2002-46704